A single amino acid substitution in the capsid protein of Zika virus contributes to a neurovirulent phenotype

Increasing evidence shows the African lineage Zika virus (ZIKV) displays a more severe neurovirulence compared to the Asian ZIKV. However, viral determinants and the underlying mechanisms of enhanced virulence phenotype remain largely unknown. Herein, we identify a panel of amino acid substitutions that are unique to the African lineage of ZIKVs compared to the Asian lineage by phylogenetic analysis and sequence alignment. We then utilize reverse genetic technology to generate recombinant ZIKVs incorporating these lineage-specific substitutions based on an infectious cDNA clone of Asian ZIKV. Through in vitro characterization, we discover a mutant virus with a lysine to arginine substitution at position 101 of capsid (C) protein (termed K101R) displays a larger plaque phenotype, and replicates more efficiently in various cell lines. Moreover, K101R replicates more efficiently in mouse brains and induces stronger inflammatory responses than the wild type (WT) virus in neonatal mice. Finally, a combined analysis reveals the K101R substitution promotes the production of mature C protein without affecting its binding to viral RNA. Our study identifies the role of K101R substitution in the C protein in contributing to the enhanced virulent phenotype of the African lineage ZIKV, which expands our understanding of the complexity of ZIKV proteins.

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Cheng-Feng Qin Sep 17, 2023
Immunofluonrescence images were acquired using Olympus BX51 microscope equipped with a DP72 camera.Origin iTC200 software (Malvern Instrument Ltd.) CD-hit program (v4.8.1) IQ-Tree (v1.6.12)ImageJ software Prism software (GraphPad) The data from ITC assay were analyzed by by using Origin iTC200 software (Malvern Instrument Ltd.).The CD-hit program (v4.8.1) was utilized, with a sequence identity threshold of of 0.995, to to select representative genomes of of the Asian lineage.The maximum likelihood phylogenetic tree of of ZIKV complete sequences was constructed using IQ-Tree (v1.6.12) with 1000 ultrafast bootstrap test.Quantification of of bands of of western blotting was performed using ImageJ software.The remaining data were analyzed using Prism software (GraphPad).

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